Fibrous adsorbents have been widely used for recovering metals from aqueous systems, such as seawater, fresh water, wastewater, drinking water, ultrapure water, and other less common types of waters, such as hot spring water and water rich in precious metals. Many of the fibrous adsorbents used for the extraction of metals have a polymeric backbone (trunk) with functionalized polymeric grafts extending out from the backbone, wherein the functional groups have metal-binding properties.
Amidoxime groups are often the functional groups of choice in many metal extraction technologies by virtue of their known higher metal adsorption (complexing) abilities compared to many other functional groups. Amidoxime groups are particularly adept in adsorbing heavy metals, such as uranium ions. Nevertheless, there would be a significant benefit in further improving the metal-binding abilities of amidoxime-containing compositions, particularly for those applications in which the concentration of the metal in solution is exceedingly low or where substantially complete removal is desired.